Automatic circuit controller for gaseous discharge devices



Feb. 2, 1943.,

A. McQERMGTT 2, 49

AUTOMATIC CIRCUIT CONTROLLER FOR GASEOUS DISCHARGE DEVICES QAX 1 Filed Sept. 9. 1940 Julian Ac Mcflezmlt;

INVENTOR.

'QWM;

Patented Feb. 2, 1943 AUTOMATIC CIRCUIT CONTROLLER FOR GASEOUS DISCHARGE DEVICES Julian A. McDermott, Elmhurst, N. Y. Application September 9, 1940, Serial No. 355,902

7 Claims.- The invention here disclosed relates to control of the circuits for gaseous discharge devices.

Objects of the invention are to protect such circuits and the apparatus forming parts of the circuits from the sudden voltage rises which normally result from such causes as the removal of a tube or the failure of a tube in the secondary circuit; to automatically continue this self protective action when normal circuit conditions are restoredand to accomplish these results with relatively simple, inexpensive apparatus, adaptable to present operating conditions.

The foregoing and other desirable objects are attained by novel features of construction, combinations and relations of parts all as hereinafter set forth, illustrated by way of example in the the accompanying drawing and broadly covered in the claims annexed.

In the drawing there is illustrated one of the commercial embodiments of the invention, but structure may be modified and changed as regards this particular disclosure, within the true spirit of the invention as hereinafter defined and claimed.

The single ,iigure in the drawing is a partial perspective and diagrammatic view illustrating structure and wiring features of the invention.

Briefly, the invention involves the utilization of certain operating characteristics of the transformers used with gaseous discharge devices and the provision of means susceptible to variations in such operating characteristics to effect desired measures of control.

Accordingly, there is shown in the illustration a transformer of the more or less conventional current limiting or constant current type of construction, modified and equipped to accomplish the purposes of the invention.

This type of transformer is constructed, as indicated, with a magnetic shunt i, between the legs 2 and 3, which carry the primary and sec- I ondary windings 4, 5 and which shunt may include an air gap at one or both ends as at 6, i, usually closed with non-magnetic material, substantially as represented in the drawing.

When the primary circuit is'closed and a gaseous discharge device, as represented by tube 8, is connected in the secondary circuit, the countermagnetomotive force set up by the secondary, forces a portion of the magnetic flux established by the primary to by-pass through the shunt field and thus to automatically reduce or limit the current in the secondary circuit, Interruptions or variations in the secondary circuit as occasioned by removal or failure of a tube,

interrupt or reduce the counter magnetomotive force and hence the magnetic flux in the shunt path. The variation from one condition to the other is governed largely by the reluctance of the air gap or gaps. 7

These variations in magnetic flux in the shunt field are utilized in the illustration for effecting desired control of the primary circuit.

Specifically, control is attained in the embodiment illustrated by provision of an armature 9, pivoted at H), across the upper air gap 6, so as to be susceptible to flux in the magnetic shunt and carrying a contact ii; cooperable with a contact l2, to close the primary circuit, through connections indicated at I 3, i4. To more or less direct the shunt flux to this armature, magnetic poles i5, iii, are shown extended from the upper leg of the'core and from the shunt core respectively toward the swinging armature.

A spring I] is shown acting on the armature in circuit closing direction to assure automatic return to the circuit closed position after the device has operated in its protective capacity.

During normal operations with flux through the shunt at a maximum, the armature is positively held in the position indicated, closing circuit through the primary winding. v

Movement of the armature to effect opening of the primary circuit is positively effected in the illustration, by a magnet it, connected at l9, directly across the supply circuit 20. This circuit opening magnet is shown as carried by a magnetic bracket or yoke Informing part of a local magnetic circuit for the magnet coil and this coil may be simply a potential winding, taking a minimum of current.

The strength or effective pull of the circuit opening magnet is so balanced in respect to the attraction exerted on the armature by the magnetic shunt that the armature will be held in the circuit closing position, so long as flux through the magnetic shunt remains normal and such magnet will become effective to open the primary circuit only when flux through the shunt drops below a certain predetermined value. The armature being subjected to the pull of the two magnetic forces, while biased in the circuit closing position, is at all times alive" and instantly responsive to pull of the circuit opening magnet and because of such opposing forces, the armature will snap fully from one position to the other.

In the illustration, with the main switch closed at 22, and an operative tube in the secondary circuit, the parts will be as represented,

that is, with the primary circuit closed at H,

l2,'and held so against the pull of the potential coil I8, by action of the magnetic flux in the shunt path on the armature 9.

With interruption in the secondary circuit as by removal or breakdown of the tube 8, the counter magneto-motive force created by the secondary winding ceases and magnetic flux through the shunt l accordingly drops. With this drop or cessation of magnetic pull at l5, IS, on the armature 9, the potential coil I8, immediately snaps the armature over, against the force of the spring ll, to open the primary circuit at II, it.

Regulations require that in servicing apparatus of the character under consideration, the main switch be thrown before tubes are removed or replaced. This insures that after a tube failure or the like, and after the apparatus has auto matically acted to open circuit through the primary of the transformer, the main switch at 22 will be opened. With opening of the main switch, preparatory to removal or replacing a tube, the potential winding will be de-energized. thus to permit the armature to drop back into the primary circuit closing position, such closing action being assured by spring l'l. Then when the defect in the secondary circuit is remedied as by replacement of a defective tube and the main switch 22 is again closed, the apparatus will function as represented, holding the circuit through the primary closed at H, l2, but ready instantly to open the primary circuit in 'case of opening or failure in the secondary circuit.

The illustration is diagrammatic in character so all details have not been shown. It will be understood however that such details as may be necessary or desirable, such .as' suitable stops limiting motion of the circuit controlling armature in both directions, dashpots or similar movement controlling or regulating devices and the like may be provided. The circuit controlling portion of the apparatus may be built onto and as a part of the transformer structure, or may be applied or connected as a separate attachment. With present transformer constructions, the magnetic studs l5, l6, may be applied as polar extensions which will project to/or through the case or cover of the transformer and the armasimply act mechanically to effect opening and closing of the circuit, that is, it need not actually carry the switch contact or contacts and merely serve to effect opening and closing movements of such contacts. Tilting mercury switch constructions may be used in place of the more or less conventional form of switch indicated.

While believed preferable to subject the armature to the pull across the gap in the magnetic shunt, it is contemplated that flux variations in any portions of the shunt may be utilized for the control purposes of this invention. While here illustrated in conjunction with a transformer of the shell type,-it will be understood that the invention is adapted to other types and forms of transformers than the particular one here shown,

. whether multiple shunts are used or not.

In the installation of the types of gaseous tube equipment herein described it is usual to connect a current limiting device in the primary. It is contemplated that wherever it is desirable to cause the current limiting device or fuse to function when an open circuit or similar condition exists in the secondary, the contactors Ii, l2 in the drawing may be reversed in position so that they remain open normally, and no series connection is made between the contact points and the transformer primary. Instead, the points are connected across the primary or line and the action of the armature if the secondary circuit was opened would be to short circuit the installation causing the current limiting device to isolate the installation. A resistor may be used in series with the contactors tolimit the short circuit current to safe values but permitting the operation of the current limiting device.

What is claimed is:

1. An automatic circuit controller for gaseous discharge devices, comprising a transformer having a magnetic shunt, an armature under control of flux in said magnetic shunt, means governed by said armature for controlling the primary circuit of said transformer and a potential Winding acting on said armature in opposition to said shunt magnetic flux and connected across the primary circuit of the transformer.

' 2. An automatic circuit controller for gaseous discharge devices, comprising a transformer having a magnetic shunt, an armature under control of flux in said magnetic shunt, means governed by said armature for controlling the primary circuit of said transformer, a potential winding acting on said armature in opposition to said shunt magnetic flux and connected across the primary circuit of the transformer and spring means acting on said armature in the circuit closing direction of movement.

3. An automatic circuit controllerfor gaseous discharge devices, comprising a transformer having primary and secondary circuits and a magnetic shunt, circuit controlling means for saidprimary circuit, an armature controlling said circuit controlling means and subjected to the magnetic pull of said magnetic shunt and electromagnetic means actuated by line voltage for effecting movement of said armature in the opposite direction.

4. In a controller for gaseous discharge devices,

.the combination of a transformer having primary and secondary circuits, means associated with said transformer for establishing opposing magnetic forces and at least one of said means being governed in strength by operating condiitions in the secondary circuit, armature means subjected to said opposing magnetic forces and biased to stand in one position during normal operating conditions in the secondary circuit and to be shifted oppositely on occurrence of abnormal conditions in the secondary circuit and circuit controlling switch means in the'primary circuit of said transformer under control of said mal conditions in the secondary circuit, circuit controlling switch means in the primary circuit of said transformer under control of said armature and means for insuring return of said armature to the circuit closing position upon de-energization of said transformer.

6; In combination, a transformer for use with gaseous discharge tubes, relay means for interrupting the primary circuit of said transformer when abnormal conditions occur in the secondary circuit of said transformer and electromagnetic means actuated by line voltage for maintaining the interruption of the primary circuit each time such action occurs.

7. An automatic controller for use with gaseous discharge devices, comprising a transformer having a magnetic shunt and a relay included in the magnetic circuit of said transformer and having a movable element under control of the flux in said magnetic shunt and switch means operable thereby for holding the primary circuit of the transformer open upon circuit interrupting action of said movable element, said element being arranged for circuit interrupting operation upon magnetic changes in said magnetic shunt on said transformer resulting from a-defect in the sec ondary circuit of the transformer.

JULIAN A. McDERMOTT. 

